Arrangement of stator-platemounted elements of a flywheel magneto



Nov. 7, 1950 A. L. BROWNLEE EIAL 2,528,687

ARRANGEMENT OF smmxmmmmounmn ELEMENTS OF A FLYWHEEL MAGNETO Filed Dec.8, 1949 2+ [Msuur/o/v [NJl/LA now INVENTOR ALuzwL bli'omuzz ANDZZ'RRz/Ycz G. .L 00/6 ATTOR EYS Patented Nov. 7, 1950 UNITED STATESPATENT. OFFICE ARRANGEMENT OF STATOR PLATE- MOUNTED ELEMENTS OF AFLYWHEEL MAGNETO Application December 8, 1949, Serial No. 131,732

1 Claims.

This invention relates to an improved arrangement of such elements of aflywheel magneto as are mounted on the stator plate, that is, all themagneto elements except the magnet and its pole shoes which are fixed tothe flywheel.

Magnetos of this type are commonly used with the relatively smallinternal combustion engines which serve as outboard motors for boats. Insome cases, such engines are of the two-cylinder, two-cycle,alternately-firing type and it is desirable that the magneto for such anengine should have two separate ignition units, that is two separatecoil-bearing core structures, for cooperation with the magnetic rotorformed by the flywheel. In such a case, two breaker mechanisms and twocondensers are required, one for each ignition unit. In other cases, onecore structure may bear a low tension coil for generating lightingcurrent, while the other core structure or structures may bear anignition coil or coils. In every case, there will be at least twocoil-bearing core structures and at least one breaker mechanism. Theproblem is to mount all the necessary elements on a stator plate, whichis adapted for use with small flywheels (frequently no more than six andone half inches in diameter), without adding to the overall dimensionsof the magneto so as to require changes in the flywheel.

This invention is an improvement on that disclosed in Patent No.2,447,727, granted August 24, 1948, on an invention of Albert 1. Alstromand Allen L. Brownlee and assigned to the assignee of the presentinvention.

The mechanism of said patent has been used successfully andsatisfactorily with outboard motors at speeds up to about 4200 R. P. M.but for motors operating at higher speeds, approaching 5000 R. P. M. orabove, said mechanism has certain disadvantages which the presentinvention seeks to overcome. A breaker mechanism of lower inertia isneeded and one in which the movable breaker point is not carried by theradially-movable cam-actuated plunger of said patent.

It is an object of this invention to mount the breaker mechanism in thenarrow radial gap between two adjacent core structures and to mount inthe most narrow portion of such gap a radially-slidable plunger, as inthe prior patent, and also to provide in the outer and wider portion ofsuch gap a pivoted 'U-shaped breaker lever having short parallel arms,one of which lies at right angles to and is actuated by" the pin: er andthe other of which carries a breaker point confronting a stationarybreaker point carried by an ear on the plate that retains the plunger inits slideway.

This object will best be understood from the description of oneillustrative example of the invention in the accompanying drawings, inwhich:

Fig. 1 is a top plan view of a stator plate embodying the invention;

Fig. 2 is a fragmentary sectional elevational view taken on line 22 ofFig. 1 and drawn to a larger scale;

Fig. 3 is a fragmentary view taken similarly to Fig. l but drawn to alarger scale;

Fig. 4 is a fragmentary sectional plan view taken on the line 44 of Fig.2; and

Fig. 5 is a fragmentary sectional elevational view taken on the line 5-5of Fig. 3.

Referring to these drawings: there is shown at l in Fig. 2 a portion ofthe. upper end of the crankcase of a small internal combustion engine,such for example, as that used as an outboard motor for boats. Thecrankcase has an external hub 2, through and beyond which one end of theengine crankshaft 3 extends. The stator plate includes a substantiallycircular bottom wall 4 from which upstands in coaxial relation a hollowhub 5. This hub 5 telescopes over the crankcase hub 2 and closely fitsthe same to support the stator elements of the magneto, and particularlythe pole pieces, in true coaxial relation with shaft 3. The hub 5 may beheld to hub 2 by any suitable means, herein shown as leather plug 6mounted in wall 4 for radial sliding movement and pressed inwardlyagainst the bottom of a circumferential groove 7 in hub 2 by means of aspring 8, which is adjustable by a screw 9, threaded into the statorplate and closing the hole in which the plug and spring are mounted. Thearrangement holds hub 5 in axial position on hub 2 and also holds itfrictionally against turning on hub 2, enabling it to be turned, whendesired, for the purpose of advancing or retarding the spark in theusual manner. The stator plate also includes an annular rim 10,extending upwardly from the bottom wall 4 and an annular flange ll,turned outwardly from the upper 'end of rim Iii. This flange H isintended to cooperate with the engine flywheel, when in place on shaft3, to provide an enclosure for the magneto parts, as shown in theabovenamed patent.

The stator plate (Fig. 1) supports a plurality of core structures, inthis case two, which are angularly spaced about hub 5. These corestructures may vary considerably in form. As herein shown, each corestructure includes three more or less radial legs l2, l3 and I4, theinner ends of which are interconnected as at [5. The outer ends of thelegs l2, l3 and I4 of each core struc ture form pole pieces forcooperation with the pole shoes of the magnetic rotor, as shown in saidpatent. The intermediate leg l3 of each core structure forms a core,bearing suitable windings, in this case primary and secondary coils l6and I1, respectively, since two high tension ignition units are desired.But in some cases one core structure might equally well bear a singlelow tension winding to be used for lighting purposes. Each corestructure is made up of iron laminations, held together by rivets I 8and clamped to supporting pads i9, which project upwardly from thebottom wall 4 of the stator plate, by screws 20.

The two core structures are located in opposed relation. The legs I2 andI4 and the connecting part I5 of each core structure are arranged inadjacent relation and are separated by narrow gaps which extend radiallyof the stator plate. The space between the central portions of the twoparts I5 is substantially less than the diameter of either hub 2 or 5.It is necessary in order to avoid undue electrical leakage losses tokeep each metallic and grounded core structure spaced away from thesecondary coil [1 thereon. Because of this, a space, such as 2|, isnecessary betweenthe inner end face of each secondary coil ll andtheadjacent legs I2 and 14 of the core structure. Therefore, the narrowradial space between the two core structures is constricted intermediateits ends at locations opposite theinner ends of the secondary coils l1.Beyond this constriction, the core structures diverge outwardly to someextent, as permitted bythe location of the pole pieces on the ends oflegs 12 and I4.

The space limitations are such as to preclude straddle the ear 28.

the use of the common type of breaker mech- 7 anism, that is the typehaving a pivoted bellcrank with widel diverging arms, the outer end ofone of which carries a breaker point and the outer end of the other Ofwhich rides directly on the actuating cam. Such a breaker mechanismcould not be located between the two closelyspaced core structuresdescribed and, if located outwardly beyond the core structures, it wouldi mean an increase in the axial dimensions of the magneto, which isundesired. The breaker mechanisms need to be kept between the limits oftwo transverse planes, one of which passes through the outer end face ofhub 5 and the other of which passes through the outer end faces of thecore structures. To keep the breaker mechanisms within these limitingtransverse planes, they must be made in a special manner and be locatedin the above described narrow radial gaps. In the present case, whereboth stators are used for ignition, two breakers are necessary but ifone stator is used for a purpose which does not require a breakermechanism, one of the mechanisms shown may, of course, be omitted.

. Upstanding from wall 4 of the stator plate and located, one in each ofthe two most narrow portions of the radial gaps between the two corestructures, are supports 22. Each support has a deep and narrow slotlocated radially of the plate and forming a slideway to slidably receivea reciprocable slide 23, and a wide and shallow slot in its upper end toreceive a fiat and relatively thin retaining plate 24 for the slide.This plate is held to the support 22 by means of a 4 screw 25, passingthrough a longitudinal slot 26 in the plate and threading into thesupport. The plate 24 holds the slide 23 against vertical movement inits slot and slidably engages the upper face of the slide. One end ofslide 23 is adapted to ride on a cam 21, fixed to shaft 3, and the otherend is adapted to engage and actuate the breaker arm of the breakermechanism. The slide is desirably made of laminated phenolic material toprovide for a long life of useful service under'severe operatingconditions.

The breaker mechanism is supported entirely fromthe plate 24, whichextends beyond the support 22lfor this purpose and has an ear 28 turneddownwardly at right angles therefrom and bearing the fixed breaker point29. Plate 24 is offset laterally (Fig. 1) to support a stud 30, which isfixed at one end to the plate and extends downwardly therefrom tosupport the breaker arm. The offset portion of plate 24 extendsoutwardly beyond the stud 38 at an acute angle to the plane of movementof slide 23 and terminates witha downturned ear 3|, having a seat 32 forthe outer end of the breaker spring 33. The breaker arm is made of anysuitable insulating material. ,It is substantially U-shaped, having twoshort and closely-spaced parallel arms 34 and 35 (Fig. 4),interconnected at one end by a portion 36, which is pivotally mounted onstud 3B. The. arm 34 carries on one side a breaker point 3'l,tocooperate with breaker point 29 and, on the other side, a flexibleconductor 33, secured to the arm bythe same rivet which holds thebreaker point 3'! to the arm. The breaker arms 34 and 35 The spring 33acts on arm 34 with a tendency to hold the breaker points 29 and 31engaged. The slide 23, when moved radially outward by cam 21, acts onarm 35 to separate the breaker points.

The spring 33 may, and preferably does, act to hold the breaker arm inaxial position on its fule c'rum stud 30. As best shown in Fig. 5, theear 3! is bent at an angle slightly less than ninety degrees to theplate 24, say The arm 34 has a face 38 arranged at a similar angle toits upper fiat face and on this face is a projection 39 to fit withinone end of spring 33, just as the projection 32 fits within the otherend of spring 33. These projections 32 and 39 hold spring 33 so that itsaxis'lies normal to the ear SI and face 38. Thus, of the force exertedby the spring 33 on the breaker arm, there is an upward verticalcomponent which presses the arm vertically upward against a washer 46 onstud 30 and the washer against the bottom face of plate 24.

Associated with each breaker mechanism is the usual condenser which iselectrically connected across the breaker points 29 and 31 in the usualmanner. This condenser is contained in a metallic cylindrical casing 4ito which one terminal of the condenser is connected. The lower end ofthis casing lies in a hole formed in the stator plate and isheld inplace by screw 42, which clamps an car 43 on the casing to such plate.The other termi nal of the condenser is connected to a central metallicpost 44, upstanding from the upper and insulated head 45 of easing 4!.The flexible conductor 38 is secured to this post 44 by a screw 48.

The part 41 is a piece of felt fixed at one end in the support 22 andhaving its other end engaging the cam 21. This felt is saturated withoil and serves to wipe the cam clean and to'lubricateit- Some of theoil'on the cam reaches'the inner end of plunger 23, and works it wayalong the plunger into the slot in support 22 to lubricate the plunger.

Adjustment of the breaker points is effected by moving the plate 24radially while screw 25 is loosened. With cam 21 positioned for its highpoint to engage the inner end of the plunger and a feeler gauge insertedbetween the breaker points 29 and 31, the plate 24 is moved until theinner end of the plunger engages the cam and the outer end of theplunger engages arm 35. The screw 25 is then tightened to hold the platein adjusted position and the feeler gauge is removed.

It is desirable to provide means for-preventing the plunger 23 fromsliding out of the slideway in support 22 when the plunger is notengaged with its actuating cam, as when the stator plate not in place onits support. This may be done simply by a small projection 48 extendingdownward-1y into a slot 49 in the upper edge of the plunger as shown inFig. 2. A similar slot may be formed in the bottom edge of the plunger50 that the latter may be placed in its guiding slot either 2 edge upand still work properly. Sometimes, the inner end of plunger 23 isconcaved to fit cam 21. In such cases, the slots 49 are locatedunsymmetrically between the ends of the plunger to compel the operatorto place the concaved end so as to engage the cam. Except for this, theslots could be located symmetrically so as to be reversible.

The electrical connections of the magneto have not been shown ordescribed as they are unnecessary to an understanding of the inventionwhich consists in a special arrangement described of the parts which arecarried by the stator plate. Reference to said patent may be had for adisclosure of such connections if necessary or desired.

The construction of the magnetic rotor and its cooperation with the corestructures of the stator may be as disclosed in said patent. Referenceis also made to said patent for the operation of the magneto if such isnecessary or desired.

This invention is characterized by an arrangement of parts on the statorplate of a flywheel magneto that enables the use of a plurality of corestructures with breaker mechanisms and condenser casings for each suchstructure mounted within the narrow space limits of diameter and axiallength that are available inside a small flywheel of the kind described.The ne essary additional parts are provided without relocation of thebreaker cam and without increase in diameter of the flywheel or in theaxial length of the same. The breaker mechanism are located entirelybetween tWo transverse planes, one of which includes the outer end i aceof hub and the other of which includes the outer end face of each corestructure, as is necessary if relocation of the breaker cam is to beavoided. This is made possible by the use of a radially reciprocableplunger of thin rectangular cross section located in the most narrowpart of one of the radial gaps between adjacent core structures toconnect the breaker cam with a special form of breaker lever which canbe mounted in the outer and wider portion of such radial gap andsupported by and be" neath an extension of the plate used to retain theplunger in its slideway.

The structure disclosed is an improvement over that of said patent inthat alignment of the breaker points is not dependent on a close fit cfthe actuating plunger in its slideway. This plunger is subjected to someside thrust by cam 21 and, unless it closely fits its slideway, it swingout or" true radial position. In the arrangement of the patent, thiswould cause the movable breaker point to be moved out of parallelrelation with the fixed breaker point. In the present con struction, aclose fit of the plunger in its slideway is not necessary and anyswinging of the plunger away from true radial position cannot swing themovable breaker point because the latter is carried by a separate lever.

What is claimed is:

1. In combination, a stator plate for a flywheel magneto, said platehaving a hollow hub with an opening and being adapted to be mounted onthat hub of an engine crankcase through and beyond which the enginecrankshaft extends, a pair of coil-bearing core structures fixed to saidplate on opposite sides of the axis of the firstnamed hub, said corestructures being mounted in opposed relation with their inner walls inadjacent relation but separated by generally radial gaps, said innerwalls in a radial location near the opening in the first-named hub beingseparated by a distance substantially less than the diameter of saidopening and from said location diverging outwardly to their outer endswhich are separated by a substantially greater distance, said platehaving a portion upstanding therefrom into the more narrow portion ofone of said gaps and having a slot therein of rectangular cross sectiondisposed radially of the plate, a plunger of similar cross sectionslidably mounted in said slot, a plate secured to said portion andconfining the plunger in its slot, said confining plate having adownturned ear bearing a breaker point and having a part oilsetlaterally to one side of said ear and extending into the wider portionof said one gap, a stud fixed to and depending from said part, a U-shaped breaker lever pivotally mounted at its mid portion on said studwith its two arms straddling said ear, a breaker point on one of saidarms confronting and engageable with the first-named breaker point, theother of said arms being engageable by said plunger to separate thebreaker points, and a spring acting on the lever to move it to engagethe breaker points.

2. In combination, a stator plate for 9, flywheel magneto, said platehaving a hollow hub with an opening therein and being adapted to bemounted on that hub of an engine crankcase through and beyond which theengine crankshaft extends, a pair of coil-bearing core structures fixedto said plate on opposite sides of the axis of the first-named hub, saidcore structures being mounted in opposed relation with their inner wallsin adjacent relation but separated by gen rall radial gaps, said innerwalls at a radial location near the opening in the first-named hub beingseparated by a distance substantiall less than the diameter of saidopening and from said location diverging outwardly to their outer endswhich are separated by a substantially greater distance, said platehaving a portion upstanding therefrom into the more narrow portion ofone Of said gaps and having a slot therein of rectangular cross sectiondisposed radially of the plate, a

" plunger of similar cross section slidably mounted said car, a breakerpoint on one of said arms confronting and engageable with thefirst-named breaker point, the other of said arms being engageable bysaid plunger to separate the breaker points, and a spring acting betweenthe lastnamed ear and said lever to move the latter to engage saidbreaker points.

3. In combination, a stator plate for a fiywheel magneto, said platehaving a hollow hub with an opening therein and being adapted to bemounted on that hub of an engine crankcase through and beyond which theengine crankshaft extends, a pair of coil-bearing core structures fixedto said plate on opposite sides of the axis of the first-named hub, saidcore structures being mounted in opposed relation with their inner wallsin adjacent relation but separated by generally radial gaps, said innerwalls at a radial location near the opening in the first-named hub beingseparated by a distance substantially less than the diameter of saidopening and from said location diverging outwardly to their outer endswhich are separated by a substantially greater distance, said platehaving a portion upstanding therefrom into the more narrow portion ofone of said gaps and having a slot therein of rectangular cross asection disposed radially of the plate, a plunger of similar crosssection slidably mounted in said slot, a plate secured to said portionand confining the plunger in its slot, said confining plate having adownturned ear bearing a breaker point and having a part offsetlaterally to one side of said ear and extending into the wider portionof said one gap, a stud fixed to and depending from said part, said parthaving an ear downturned from its outer end at an angle slightly lessthan ninety degrees, a U-shaped breaker lever pivotally mounted at itsmid portion on said stud with its two arms straddling said ear, abreaker point on one of said arms confronting and engageable with thefirst-named breaker point, the other of said arms being engageable bysaid plunger to separate the breaker points,

said lever having a face paralleling the lastnamed ear, and a coilspring acting between the latter and said face to move the lever toengage said breaker points and exerting an upward thrust on the breakerlever to retain it in axial position on said stud.

4. In combination, a stator plate for a flywheel magneto, said platehaving a hollow hub with an opening therein and being adapted to bemounted on that hub of an engine crankcase through and beyond which theengine crankshaft extends, a pair of coil-bearing core structures fixedto said plate on opposite sides of the axis of the first-named hub, eachsaid structure including three legs interconnected at their inner endsnear said axis and extending outwardly in angularly spaced relationterminating with curved polar surfaces coaxial with said hub, said corestructures being mounted in opposed relation with their inner walls inadjacent relation but separated by generally radial gaps, said innerwalls at a radial location near the opening in the first-named hub beingseparated by a distance substantially less than the diameter of saidopening and from said location diverging outwardly to their outer endswhich are separated by a substantially greater distance, said platehaving a portion upstanding therefrom into the more narrow portion ofone of said gaps and having a slot therein of rectangular cross sectiondisposed radially of the plate, a plunger of similar cross sectionslidably mounted in said slot, a plate secured to said portion andconfining the plungerin its slot, said confining plate having adownturned ear bearing a breaker point having a part offset laterally toone side of said ear and extending into the wider portion of said onegap, a stud fixed to and depending from said part, a U-shaped breakerlever pivotally mounted at its mid portion on said stud with its twoarms straddling said ear, a breaker point on one of said armsconfronting and engageable with the first-named breaker point, the otherof said arms being engageable by said plunger to separate the breakerpoints, and a spring acting on the lever to move it to engage thebreaker points.

5. In combination, a stator plate for a flywheel magneto, said platehaving a hollow hub with an opening therein and being adapted to be.

mounted on that hub of an engine crankcase through and beyond which theengine crank-- shaft extends, a pair of coil-bearing core structuresfixed to said plate on opposite sides of the axis of the first-namedhub, said core structures being mounted in opposed relation with theirinner walls in adjacent relation but separated by generally radial gaps,said inner walls at a radial location near the opening in thefirst-named hub being separated by a distance substantially less thanthe diameter of said opening and from said location diverging outwardlyto their outer ends which are separated by a substantially greaterdistance, said plate having a portion upstanding therefrom into the morenarrow portion of one of said gaps and having a slot therein ofrectangular cross section disposed radially of the plate, a plunger ofsimilar cross section slidably mounted in said slot, a plate secured tosaid portion confining the plunger in its slot, said 0011-.

fining plate having a downturned ear bearing a breaker point, acondenser casing fixed to and upstanding from said stator late at alocation spaced radially outward from said ear and in the wider part ofsaid one gap near one of said inner walls, said confining plate having apart offset laterally to one side of said ear and extending into thewider part of said one gap with its outer end located between thecondenser casing and the other inner wall, an ear downturned from theouter end of said part, a stud fixed to and depending from said partnear its inner end, a U- shaped breaker lever pivotally mounted atitsmid portion on said stud with its two arms straddling said ear, abreaker point on one of said arms confronting and engageable with thefirst-named breaker point, the other of said arms being engageable bysaid plunger to separate the breaker points, and a spring acting betweenthe lastnamed ear and said lever to move the latter to engage thebreaker points.

ALLEN L. BROWNLEE. TERRENCE G. LOUIS.

REFERENCES CITED UNITED STATES PATENTS Name Date Alstrom Aug. 24, 1948Number

